The preparation of micro-particles and nano-particles is principally used to retard dissolution of active principles, and, because of this finds, numerous applications in the field of controlled-release medicaments as well as in the field of taste-masking of medicaments intended for oral administration. It has, nevertheless, always been difficult to make a satisfactory formulation containing micro-particles or nano-particles in the form of unitary doses, and in particular a suitable formulation for oral administration.
In effect, industrial preparation of tablets and capsules requires flow and/or cohesion qualities of the granulated product which is to be divided, which micro-particles and/or nano-particles do not necessarily possess.
Tablets pose problems of integrity of the micro-particles and/or the nano-particles under the effect of compression; their slow disintegration speed does not always allow administration after disintegration and suspension in a glass of water.
Capsules do not always permit dispersion of the particles in the gastro-intestinal tract.
In addition, both capsules and tablets pose swallowing problems, which are particularly marked in the young and the old.
Finally, sachets are a pharmaceutically costly form which is not suitable for ambulatory use, and the dry-syrup form is not often feasible because of the premature liberation of the active principle from the micro-particles and/or nano-particles, or because of the physical and/or chemical stability of the preparation.
French Patents 2,036,890 and 2,366,835 describe pharmaceutical forms having the characteristic of dissolving or disintegrating rapidly in an aqueous medium or in saliva.
It has now been found that techniques having totally opposed objectives, such as delay of dissolution of an active principle on the one hand, and rapid disintegration or dissolution of the pharmaceutical form on the other hand, can be combined in a novel lyophilized unitary form, which is able to disintegrate easily and rapidly in water, which contains micro-particles and/or nano-particles, and in which settling and/or rising to the surface of the said particles during lyophilization has been avoided.